At the start of 1980 I thought of myself as a science fiction writer, albeit a profoundly unpublished one. I'd wanted to be a writer since primary school and had started trying to write novels when I was 14, finally producing something loosely fitting the definition two years later: a spy story crammed with sex and violence (I still scorn the idea of only writing what you know about). It was written in pencil in an old ship's logbook, and I didn't even bother typing it up; I'd already decided it was juvenilia. The next novel owed something - arguably an apology - to Joseph Heller's Catch-22 and remains the only book I've ever started without a plan. Lacking a built-in off switch, it tumoured its way to about 400,000 words before I finally got the blighter wrestled to the ground and tied off. That one was typed, and eventually accrued an impressive collection of publishers' rejection slips.

The following three novels, written between 1974 and 1979, were SF, because I'd decided that was what I was: a science fiction writer. It was my genre. I enjoyed the classics and loved contemporary mainstream literature, but I adored science fiction as the exemplary arena of the unfettered imagination, and so that was what I would write, probably for the rest of my career, once I actually had one.

More rejection slips. More rejection slips from a smaller number of publishers, as fewer had SF lists within which to bring my deathless prose to an unsuspecting but, I was certain, ultimately extravagantly appreciative and indeed rightly thankful public.

So by 1980 I was getting fed up. Maybe I wasn't just an SF writer, after all. Maybe I should try writing an ordinary, boring, mainstream novel. Maybe it was even time to consider writing a second draft of one of these works of patent genius, rather than trusting that London publishers would have the wit to recognise an obvious rough diamond who, a trifling number of easily polished awkwardnesses having been dealt with, was surely about to make the ungrateful wretches millions . . .

The Wasp Factory represented me admitting partial defeat, heaving a slightly theatrical sigh, stepping reluctantly away from the gaudy, wall-size canvasses of science/space fiction to lay down my oversize set of Rolf Harris paint rollers, pick up a set of brushes thinner than pencils and - jaw set, brows furrowed - lower myself to using a more restricted palette and to producing what felt like a miniature in comparison.

I'd grown up in Fife and Gourock/Greenock; I suppose I could have attempted some piece of gnarly Scots realism. I'd been to university; I might have gone for a studenty campus novel. I'd not long moved to London so could have essayed a Bumpkin in the Big, Bad City book.

In the end I went for something that kept me closer to my by-then comfort zone: a first-person narrative set on a remote Scottish nearly-island told by a normality-challenged teenager with severe violence issues allowed me to treat my story as something resembling SF. The island could be envisaged as a planet, and Frank, the protagonist, almost as an alien. I gave in to the write-what-you-know school but with a dose of skiffy hyperbole, mining my own past for exaggerateable experiences. I'd built dams; Frank would too, though with a slightly psychotic uber-motif involving women, water, the sea and revenge. I'd constructed big home-made kites; so would Frank, and use one as a murder weapon. Along with a pal, I'd indulged in the then not-uncommon and perfectly innocent teenage boy pursuit of making bombs, flame-throwers, guns, giant catapults and more bombs; Frank would too, though alone and with a more determinedly harm-minded intensity.

Beyond that, it was supposed to be a pro-feminist, antimilitarist work, satirising religion and commenting on the way we're shaped by our surroundings and upbringing and the usually skewed information we're presented with by those in power. Frank is supposed to stand for all of us, in some ways; deceived, misled, harking back to something that never existed, vengeful for no good reason and trying too hard to live up to some oversold ideal that is of no real relevance, anyway. There are places, too, where I was trying to use Frank to express something about the stated and real reasons for brutality (hence Frank's musings on the attack on the rabbit warren).

I was also trying to make the point that childhood innocence isn't - and wasn't - as most people seem to imagine it; children probably harbour quite as many violent thoughts as adults, they just don't usually possess a sophisticated moral framework within which to place them.